With the accelerating of the industrialization process, the urban population density is increased, and environmental pollutions such as exhaust gas, dust, noise or the like are aggravated increasingly, which badly damage the physical and psychological health of citizens. Therefore, it is imperative to increase the green area of a city. However, the green area on the ground of a city is limited, and thus vertical greening, in particular roof greening should be developed. At present, a grass carpet is generally used for greening a roof. In the prior art, planting methods for roof-greening grass carpets using for establishing a turf in one step all include a growth medium, wherein the growth medium consists of plant waste or household garbage, sawdust, yellow soil, synthetic fertilizer, quicklime, cement, bone meal or the like. And the cultivation method for the roof-greening is described as follow: firstly the growth medium is prepared; then the growth medium are carried to the roof and further evenly placed on the roof. After that, rootless seedlings of sedum lineare are further sowed on the growth medium, and a few of nutrition media are covered onto the seedlings; or the rootless seedlings of the sedum lineare are planted on the growth medium by a cuttage method. After planted, the seedlings should be frequently watered. It is possible to put into use only after at least 30 days. The disadvantages of the above cultivation method lie in that:
(1) Raw material sources of the growth medium are narrow, which is bad for the promotion of the use of the above cultivation method. Besides, the growth medium only made from plant waste is prone to have pests living therein, and to get rotten. Besides, plants such as sedum lineare may be easily infected, or damaged by the pests, in such a way that the growth of the plants may be affected.
(2) The growth medium is loose, such that it is easily washed away by rains and causes soil erosion. For the growth medium is loose before the sedum lineare is survived to establish a turf, most of the growth medium will be washed away and lost as a result when coming across a large rainfall. Besides, washing by the rains or watering for a long time may result in a loss in the growth medium, which will influence the growth of the sedum lineare later. Furthermore, the growth medium washed away may block sewers or lead to a pollution to the ground of the building, and a situation that the seedlings of the sedum lineare being a mess or washed way may occur, in such a way that a cover degree of the turf established is uneven.
(3) The sedum lineare will survive quickly only by being watered frequently at a pre-growing stage of growth. Therefore, not only a watering apparatus should be reinstalled to communicate with a watering plant, but also the administrator should go up and down frequently, which is inconvenient.
(4) Due to the growth characteristics of the sedum lineare and the climate conditions, the sedum lineare grows slowly or stop growing in winter or summer. In this way, it is impossible to ensure that the establishment may be implemented all the year round by the method with the growth medium.
Due to the disadvantages described above, a wide promotion and application of the roof-greening are greatly limited.